Diamond powder or bort formed during the grinding of diamonds



Dec. 6, 1955 5. R008 2,725,696

' DIAMOND POWDER OR BORT FORMED DURING THE GRINDING OF DIAMONDS F'iled Dec. 23, 1953 2 Sheets-Sheet l IN V EN TOR.

Dec. 6, 1955 s. ROOS 2,725,596

DIAMOND POWDER OR BORT FORMED DURING THE GRINDING OF DIAMONDS Filed Dec. 23, 1955 2 Sheets-Sheet 2 IN VEN TOR.

tains a minimum amount of bort. hood through which the diamond .holding means are passed, can be left open because the rotation of the grinding disc causes a current of .air which is .directed United States masses DIAMOND POWDER R liilRT FORMED DURING THE GRINDENG 61F DllAl /EGNDS Siegfried Roos, Amsterdam, Netherlands, assignor to Jozef Komkommer, Amsterdam, Netherlands Application December 23, 1953, Serial No. $9,359

Claims priority, appiication Union of Sleuth Africa January 3, 1953 9 Claims. (Cl. 51-27%) The present invention relates to an apparatus for recovering bort formed during the grinding of diamond on a horizontal grinding mill, in which apparatus at least one substantially radially directed catching screen is so provided against the lower side of a hood arranged over the grinding disc as to be slightly spaced from and to be distributed in circumferential direction over the upper .curnferential edge on a sub-structure comprising a circular tray-shaped bodyhaving a central aperture in .its

bottom and a covering platehaving a central aperture,

said plate being located at some distance above said bottom and closely below the grinding disc and one or a plurality of blades or retaining screens provided between said bottom and said covering plate.

According to the invention this device can be received in a correspondingly shaped aperture in a table or like support, the grinding disc being driven via this aperture which registers with the central apertures in thesub-structure, by means of a vertical shaft passing through said apertures.

Such a device operates in the manner of a cyclone separator. When the grinding disc rotates the air below the hood is brought into turbulence and together with the bort which is formed therein by the grinding of .one or more diamonds, it is hurled against the blades of the hoodand via said blades and the upstanding wall of the tray of the substructure it is hurled against the blades of said substructure to be eventually discharged via the central apertures in the table and in the substructure.

By covering the blades of the hood and/or the upstanding wall of the tray and/or blades of the substructure at the side cooperating with the air with a bort-retaining coating, e. g. steel wool, gauze or the like provided with a sticky substance which retains the bort,

it is possible to achieve that the air discharged only con- The openings in the towards the sub-structure.

According to theinvention this sub-structure can carry the bladesin a detachable manner, which is desirable in order to enable the blades to be replaced by new ones when they have sufiiciently performed their function of recovering bort.

According to another embodiment of the invention pairs of bort catching and retaining blades are secured to the bottom of the sub-structure, the blades of each power.

- be generated by the rotating disc 1. Bart origin 2 pair bClBgiCllWfid inwardly andspaced tron-tone another, and the pairs of blades being also spaced from one another, each blade extending from a pointat some distance from the upstanding wall of the sub-structure .towards the edge of .the central aperture in the bottom of :the sub-structure.

In both embodiments of the invention the hood may consist of plastic or another material having or capable of-taking an electrostatic charge.

The drawings illustrate the invention :by means of an embodiment of the apparatus.

vFig. 1 is a vertical section of an apparatus according to the invention on line I-I,in Fig. 2;

Fig. 2 is a plan view thereof;

.Fig. 3 shows a construction detail;

Fig. 4 is a vertical section on theline .IVIV :in Fig. 5 of an apparatus of modified construction, .the elements contained within the tray-shaped body of said apparatus bei g shown in elevation;

' .7 shows a plan view of this apparatus, the hood wing taken away and the horizontal grinding disc being 13' broken away;

,. 6 is a plan view of the hood separately;

Fig. 7 shows a detail (one blade) of the hood.

"in this embodiment azflat hood 3 is arranged over a horizontal grinding disc 1 which'is secured on a'vertical spindle 2, which spindle extends downwards from the grinding disc 1 and which can be driven by asource'ot The hood 3 is provided with fourrectangular openings 4 whichextend in radial direction and whichare uncovered and which. servefor passing .thediamondholding nieanstheredarough. The "hood .3 made e. v g. from transparent plastic, has itsinnertside providedwith e. .g.

plastic catching screens or blades 5, the under side :of

which screens or blades '5 is located closely above the grinding disc. The hood 3rests with :itscircumferential edge on a substructure comprising a circular tray-shaped body 6 having a central aperture V7 in its bottomand the upstanding wall of which is provided with a rim18 body 6 and parallel to said bottom a covering plate '10 provided with a central aperture 9 is arranged, which plate has its upper side located closely below the grinding disc 11. ,In three places lips 11 are bent downwardly out of the covering plate 10; to each lip 11a curvedcatching screen or blade 12 ;is detachably secured by means of .a

screw :13 which runs parallel .to'the covering plate -10. Each of these blades 12.is furthermore detachably connected with the'bottom of the tray-shaped body by-rneans of vertical screws 14; the blades, therefore, are the supports of the covering plate and keep this plate in its :place because .they are secured to the said bottom.

.In addition to theabove mentionedblades 2, to which the lips 11 are secured, .there are blades 15 to which no lips are-secured, but which otherwise are identical to the blades 12,. .Each blade 15 is located midway between :twoblades 12. .Theblades 12 and 15' have a recessed central portion, the :recess'or chamber being designated by the numeral 16. The screws 14 securing the blades tozthe'bottom of;the 'tray are screwed into the bottom ..of the chambers 16.

When the device is inoperation, a currentoi air-will sequently be hurled against the inner side of the upstanding wall of the tray-shaped body 6, which wall (in a manner not shown) is covered with gauze provided with a sticky bore-retaining substance, so that the air will again be stripped of some bort, whereupon the air will finally strike against the concave sides of the blades 12, 15 which are covered in a similar manner (not shown), the air being eventually discharged with as small as possible an amount of bort suspended therein, through the central aperture in the bottom of the tray-shaped body 6. The covering of the concave side of the blades 12, 15 may consist of steel wool provided with a sticky bortretaining substance.

In the embodiment according to Figures 4-7 the main elements are identical to the main elements of the embodiment according to Figs. 13. A flat hood 3 is arranged over a horizontal grinding disc 1 which is secured on a vertical spindle 2, extending downwards from the grinding disc 1 and adapted to be power-driven.

The hood 3, which in this embodiment consists of two halves, is made of transparent plastic and is provided with four elongated openings 4 and two smaller elongated openings 17. All of said openings extend in radial direction and are uncovered; the openings 4 serve for passing the diamond holding means therethrough and for the entrance of air; the openings 17 serve also for the entrance of air between the adjacent openings 4. The hood 3 is provided internally with bort catching screens or blades 5, which are integral with the hood proper and which with their under side are located closely above the grinding disc 1.

The hood 3 rests with its circumferential edge on a sub-structure comprising a circular tray-shaped body 6 having a central aperture 7 in its bottom 18 and the upstanding wall of which is provided with a rim 8, forming an accommodation for the circumferential edge of the hood 3.

To the bottom 18 of the tray-shaped body 6 six pairs of bort catching and retaining blades 19, 20 are attached so as to be uniformly distributed over the circumference of said bottom. Each blade 19 has one end portion 21 circularly bent parallel or about parallel to the circular upstanding wall of the tray-shaped body 6 and spaced therefrom; the remaining portion 22 of each blade 19 is curved inwardly and extends up to the edge of the central aperture 7. Each blade 20 is uniformly curved throughout its length and extends from the free extremity of the circularly bent end portion 21 of a blade 19 up to the edge of the aperture 7.

The curvature of the blade 20 is the same as that of the portion 22 of the blade 19 and the blades 19 and 20 of a pair are spaced from one another. The six spaced sets of pairs of blades 19, 20 are encircled by a perforated, circular partition 23 spaced from the upstanding wall of the tray-shaped body 6. A covering plate rests on the sets of blades 19, 20. This covering-plate is provided at its circumferential edge with three clips 24 adapted to slidably engage corresponding outwardly bent lips 25 attached to the outer side of the circularly bent end portions 21 of three of the blades 19.

The inner surface of the hood 3 the inner side of the upstanding wall of the tray-shaped body 6, the inner side of the bottom 18 of this body and all of the blades of the hood and of the sub-structure are covered by a bortretaining means, e. g. a sticky substance.

The perforated partition 23 may also be coated with a bort-retaining means; this partition prevents small diamonds inadvertently fallen down through the openings 4 in the hood 3, from finding their way down through 4 the central aperture 7; they will now be received in the circular space 26 between the upstanding wall of the trayshaped body 6 and the perforated partition. The operation of this embodiment will be clear after what has been described in connection with Figs. 13.

I claim:

1. In apparatus for recovering bort formed during the grinding of diamonds on a grinding mill having a horizontal grinding disc, a sub-structure comprising a circular tray spaced below said disc and having a central aperture in its bottom, said tray having an upstanding wall at its periphery, a covering plate having a central aperture, said plate being located at some distance above the bottom of said tray and closely below said grinding disc and at least one catching screen provided between said bottom and said covering plate, and a hood arranged over the grinding disc and supported at its periphery by said upstanding Wall of said tray, at least one substantially radially directed catching screen on the lower face of said hood, said screen being slightly spaced from, and distributed in a circumferential direction over, the upper face of said disc.

2. An apparatus according to claim 1, characterized in that the grinding disc is driven by means of a vertical shaft passing through said apertures.

3. An apparatus according to claim 1, characterized in that the catching screens of the sub-structure are detachably secured both to the bottom of the tray and to the covering plate.

4. An apparatus according to claim 3, characterized in that lips are bent downwardly out of the covering plate, to which lips the catching screens are detachably secured.

5. An apparatus according to claim 1, characterized in that selected surfaces of members comprising the hood, the upstanding wall of the substructure and the various blades are coated by a bort-retaining means.

6. An apparatus according to claim 1, characterized in that the covering plate is integral with at least one bort catching and retaining blade.

7. An apparatus according to claim 1, characterized in that pairs of bort catching and retaining blades are secured to the bottom of said tray, the blades of each pair being curved inwardly and spaced from one another, and the pairs of blades being also spaced from one another, each blade extending from a point at some distance from the upstanding wall of the sub-structure towards the edge of the central aperture in the bottom of the substructure.

8. An apparatus according to claim 7, characterized in that the pairs of blades are encircled by a perforated partition spaced from the upstanding wall of the substructure.

9. An apparatus according to claim 1, characterized in that the hood consists of plastic or another material having or capable of taking an electrostatic charge.

FOREIGN PATENTS 108,742 Austria J an. 25, 

